Electric lamp



(No Model.)

B. THOMSON.

ELECTRIC LAMP. No. 320,018. Patented June 16, 1885.

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UNITED STATES PATENT OFFICE.

ELIHU THOMSON, OF LYNN, MASSACHUSETTS.

ELECTRIC) LAMP.

SPECIFICATION forming part of Letters Patent No. 320,018, dated June 16, 1885,

Application filed November 22,1884,

To all whom it may concern:

Be it known that I, ELIHU THoMsoN, a citizen of the United States, and a resident of Lynn, in the county of Essex and State of Massachusetts, have invented certain new and useful Improvements in Electric-Arc Lamps, of which the following is a specification.

My present invention relates to the carbonseparating and feed-regulating mechanism for electric-arc lamps; and its purpose is to attain great delicacy of action with small current expenditure, as also to avoid the use of differential magnets or coils where the force available for adjustment is only the difference between the forces of the magnets, which necessitates the employment of large and powerful magnets, and a consequent considerable waste of current in energizing them, owing to the fact that they are always traversed by current during operation.

In my present invention I employ a magnet in the main or line circuit whose ofiice is to raise the upper carbon and form the arc, in combination with a derived-circuit magnet acting in opposition to a suitable retractor, the function of which latter magnet is to con trol the flow of current in the main-circuit magnet by acting upon suitable contacts,which govern the flow of current in the main-circuit magnet by shunting current, breaking circuit, varying resistance, or by acting in any other suitable way known in the art, so as to vary or control the flow of current in an apparatus by switch or circuit controlling devices.

In so far as I have described the combination its devices and action are similar to those of the patent to Houston and Thomson, No. 223,646, although the special devices for magnets, contact-s, &c., used herein differ somewhat.

The distinguishing characteristic of my present invention lies in making the two por tions or electrodes of the controlling-switch or contact closing or varying device movable, one portion (to wit, that which was in the prior patent fixed) being made to follow the movement of the armature or other parts moving under the lifting action of the maincircuit magnet, while the other, as before, is moved by the action of the derived-cireuit .magnet. By this arrangement I secure im- (No model.)

portant advantages in delicacy and certainty of action, as will be apparent.

I11 the accompanying drawings, Figure 1 is a front elevation of a lamp embodying my invention. Fig. 2 is a diagram of the circuits. Fig. 3 is a detail of a lamp-magnet. Fig. 41. shows a modified form and arrangement of lamp-magnets. Fig. 5 illustrates a form of switchor circuit controller that may be use in varying the flow of current in the 11111111 lifting magnet. Fig. 6 shows a wellknown kind of feed regulating mechanism, which is an equivalent of the clamp or clutch illustrated in other figures.

D indicates the main or coarse wire liftingmagnet, which is placed, as indicated, in the circuit from X to Y, through the carbon carrier or rod R, and the carbons E E in any usual or desired manner. Its armature N and lover L, carrying the armature and pivoted at 1), supports a carbon-lifting and feed-regulating device 01' any description, such as a clamp or clutch or a gear'train gearing with the rod R. Such feedregulating device is here typified, however, by a clamp or clutch, O, of the general character described in previous patents to me, which clamp serves to raise the rod B when it is lifted by the agency of the magnet D, or to permit the rod to slip downward when it is lowered against its releasing-stop through a weakening of the magnet Ds power. A dash-pot, J, checks sudden movements of the lever L and clutch. The magnet D may be in the line-circuit or in the carbon branchonly It is herein shown in the line-circuit, the derived-circuit branch being taken off from a point between the magnet and the carbon E, instead of from a point at the other side of the magnet.

The derivedcircuit magnet of high resistance is indicated at K. Such magnet is placed in the derived circuit around the arc in any usual or desired manner, as by electrically connecting one of its ends with the rod R, or with the frame with which the rod is in connection, and its other end to the terminal Y, as indicated. This magnet attracts its armature N,

mounted on a lever pivoted 011 against the opposing influence of any suitable retract-oras, for instance, a spring, Swhich may be made adjustable by a nut or otherwise, as indicated at A. The two parts or electrodes of a circuit-controller, switch, or contact-varying device are indicated, respectively, at O and T, one of them, T, being mounted upon lever L or some support moving therewith, and the other, 0, being carried by the lever L of the derived-circuit magnet. In the present instance the eircuit-controller is made to vary the flow of current in the magnet D by shunting current from it, and for this purpose the insulated contact or electrode 0 is connected by a flexible wire, 9, or otherwise, with the entering-wire X, at one side of magnet D, while the contact or electrode T is put in connection with the other terminal of the magnetor that leading to the red It, as indicated; hence when the contactsO T are closed the magnet D is shunted in great part thereby, the amount depending upon the size and nature of the contacts and the resistance of D. It is preferable to have, besides, a permanent resistance, V, as a shunt around D, and made so as to be easily varied for adj usting the strength of D. The connections of circuit are more clearly shown in Fig. 2, which has all corresponding parts similarly lettered to Fig. 1. The adjustments are such that upon putting current upon the lamp, the carbons being together,clutch Obeing down and released, the following actions will occur: The passage of current through D causes it to attract its armature N and move lever L so as to lift the clutch O, grip the rod R, and lift the upper carbon, E. The magnet D continues its lift until an arc is formed, either directly by the lift or by combustion of carbon, such that the magnet K in derived circuit to the are is energized, so as to attract its armature N,and finally to close the contact at O T. The immediate effect of this is to weaken the magnet D by shunting current from it; hence an immediate release of the armature N takes place, which, however, involves the opening of contact at O T by the falling away of T from O. This causes immediate reclosure of O T by the renewed strength of D. In practice a light contact is finally maintained at O T, except when too low a resistance of are occurs. The light contact is maintained while a gradual lowering of the clutch and rod R to feed takes place. \Vhen the clutch reaches the feedingpoint,it is released from the rod R. The rod It moves downward a small distance an d repeats the operation of feeding as often as may be required. Should an over-feed occur,a new are is'formed consequent upon the relaxation of the force of K, due to too close approximation of carbons, said relaxation fully opening the contact at O T.

Since the magnet K is only required to close a contact, its power to provoke a feed is practically independent of its exerting mechanical force to depresslever L. Moreover, its action is nearly, if not quite, independent of the strength of the magnetic force of I). It is advisable, however, as a saving of current, to give to I) but little surplus power over what is required to lift the carbons to form the arc.

The form of the magnets is obviously immaterial. It is preferable, however, to use twopole or horseshoe magnets, such as are indicated in Fig. 3. In addition the construction should be preferably such that the available force for liftingthelever L or moving the lever L shall not greatly differ for different positions of the armatures. This end may be secured in various ways, involving either peculiarities in the retracting or weighing devices which oppose the magnetic pull or peculiarities in the form or construction of the magnet, such that the magnetic pull shall be the same for the same strength of current in the various positions of the armature or core.

As indicated in Figs. 1. and 3, the armature may be perforated and the pole of the magnet be conoidal and project through the perforations, as described in a prior patent granted to me; or axial magnets may be used, as indicated in Fig. 4. Here the magnets Dand Kare double-axial magnets, whose cores N N occupy the relation of the armatures in the preceding figures. Of course in this case the spring S would be unnecessary should the downward gravitating tendency of the double core N be a sufficient restraint to the power of the magnet K K. The dash-pot action may in this case be obtained by a fairly close fit of the cores in the tubes upon which the coils are wound, which tubes are closed at the upper end. The inclosed air (lamps the suddenness of movement that would otherwise take place.

The contact at O T may be multiple or variable, as indicated in Fig. 5, where the part 0 is represented as a split spring making more or less complete contact 011 T, so as to give the effect of variable resistance. The action is practically as before described.

Other feed mechanisms than clutches are adaptable to the magnetic parts of my invention and the currentdivisions. For instance, the well-known device of a wheel-work supported on a lever and geared to the carbon rod or carrier may be employed. A typical form of such a mechanism is shown in Figure 6. The lever supporting the wheel-work is raised and lowered by the action of the armaturelever L in obvious manner, with the effect of lifting the rod R or of permitting the same to move downward through the release of the wheel-work by disengagement of one of the rotating arms on from the stop or catch a.

I do not limit myself to the precise c011- structions herein shown, as number-less varia tions may be made in this respect without departing from the invention, the gist of which consists in making one part of the circuit-controller switch or variable-resistance device move with the lifting devices worked by the main-circuit magnet, and operating the other or opposite portion by the influence of the derived-circuit magnet.

What I claim as my invention is 1 The combination of a main-circuit magnet, a derived-circuit magnet, and a circuit-- ICC controller, which governs the flow of current to the main-circuit magnet, one portion or electrode of said controller being movable with the core orarmature of the main-circuit magnet, while the other is governed or actuated by the derived-circuit magnet.

2. The combination, with a main-circuit lifting-magnet and a derived-circuit magnet, of a circuitcontroller both contacts or portions of which are movable, one with the parts actuated by the main-circuit magnet, and the other with the parts actuated by the derived-circuit magnet, as and for the purpose described.

8. The combination, in an electric lamp, of a lifting armature orlever, an actuating maincircuit magnet therefor, a derived-circuit mag" net, and a switch controlling a shunt around the main-circuit magnet and governed by the derived-circuit magnet, one portion of said su itch being operated by the lifting-lever and made to follow the movements thereof, as and for the purpose described.

4. The combination, in an electric lamp, of a lifting-lever and main-circuit magnet, a derived-circuit magnet, a branch around the main-circuit magnet, and a variableresistance switching device controlling the flow of current in said branch, one portion of said switch device being carried by the liftinglever, while the other portion is actuated by the derived-circuit magnet, as and for the purpose described.

5. The combination, in an e1ectric-arc1amp, of a main-circuit magnet, a lifting-lever actuated thereby,a lifting and releasing feed mechanism, as described, supported thereby and acting to hold and raise the carbon when moved in one direction, a stop or dctent acting upon the lifting devices to permit the carbon to feed downward relatively to said device when the latter is moved in the other direction to a predetermined extent, a derived circuit magnet having an independent retractor, and a circuitcontroller controlling a branch around the main-circuit magnet, said circuit controller being governed in its shunting action by the variations of force in the derivedcircuit magnet consequent-upon variations in the length of are.

6. The combination, in an electrie-arclamp, of a main-circuit magnet and a derivcdcircuit magnet, a circuit-controller governing the flow of current in the main-circuit magnet, one portion of said controller being connected with the device moved by the maincircuit magnet and carried in one direction under the influence of the increased current in said magnet and the other portion being eonnected with devices operated by the derivedcircuit magnet in an increase in the length of arc to carry such portion in an opposite direetion.

7. In an electric-arc lamp, the combina tion of a lifting-lever, L, actuated by a maincircuit magnet, a feedgoverning mechanism supported thereby, a switch contact or surface carried by said lever, a derived-circuit armature-lever,a second contact carried thereby, and a branch around the main-circuit magnet completed through said contacts.

Signed at Lynn, in the county of Essex and State of Massachusetts, this 17th day of No vember, A. D. 1884.

ELTHU THOMSON.

Witnesses:

E. J. RICHARDS, \V. O. \VAKEFIELD, 

